It’s super interesting to think about though! Imagine if your Google Doc said something like “The stolen cash is hidden in these six places, but the prosecutors don’t seem to have anything linking me to some of those areas, so I should point that out at trial.” If the government didn’t already know where the cash was hidden, it seems implausible to me that any judge wouldn’t let them have that information. It likewise seems implausible that the judge would let the prosecutors know what the defendant thinks would be good or bad to emphasize at trial. So I’m guessing it’d be an in-camera review resulting in a redacted document just disclosing the places where the cash was hidden, but not the subsequent mental impressions. But the real question, as you asked, is whether you can actually put that in front of a jury to show guilt. And I’m afraid I’m going to have to plead ignorance here (but hope there are some criminal attorneys lurking on HN that could speak to this).
It also doesn't help when your opponent hit the provider ex parte with a subpoena and they just served it up which I can speak from experience many providers are pretty eager to do. Maybe after the fact you get an order for your opponent to destroy and not use the material but if you're dealing with a party that was dishonest enough to bring a frivolous claim in the first place that may not be that comforting.
[1] https://www.floridabar.org/the-florida-bar-journal/the-work-...
[2] https://en.wikipedia.org/wiki/Work-product_doctrine
[3] https://coxlawflorida.com/florida-rules-of-civil-procedure/r...
[4] https://tenthings.blog/2019/06/05/ten-things-a-primer-on-the...